Psalm 147 is a prime example of how the Psalms can be both 'nature' psalms and songs celebrating God's covenant with Israel at the same time. Are we talking about God building up Jerusalem, or about God creating and maintaining the stars? Is the theme that God's word melts the ice, or is it that God's word is sent to Israel for their obedience? Ultimately these things cannot be unpicked. Here are some slightly jumbled thoughts on the Psalm.
1. Creation is not in itself the covenant. There is a particularity about what God does for Israel which is lacking in creation - "he has not dealt thus with any other nation". That God chooses Israel to be the witness of his glory (not least his glory revealed in creation!) is not just another part of the unfolding of creation itself, but is something subsequent and new. (Although sometimes it seems to be prior and older - the building of Jerusalem takes precedence over the creation of the stars!)
2. Creation is not a neutral sphere within which the covenant is enacted. Israel is governed by God's word - "his statutes and rules" - but so, in its own way, is the snow and ice and water - "he sends out his word, and melts them". There is continuity in the way God works, and he is absolute Lord over all he has made.
3. Creation and covenant derive from the same power and evoke the same praise. The greatness of God is revealed in his healing the broken-hearted of Israel, and in his giving the stars their names and number.
4. Creation exists for the covenant, but there is 'gratuitous' overflow. God fills Israel "with the finest of the wheat" - creation is geared up to provide covenant blessing. But then, he also feeds the young ravens! Though God's delight is in those who fear him and hope in his love, that same love overflows to those who cannot fear him and hope in him.
5. It is pleasant to sing praise to God for his glory in creation and covenant. When creation is seen in the light of God's dealings with Israel, there seems to be a return to the 'it was good' of Genesis 1. Here is a positive delight in the works and ways of God which it wouldn't hurt us to imitate!